1. Field of the Invention
This invention relates both to solving the disposal problem of heavy ends waste generated from the manufacture of chlorinated hydrocarbons such as ethylene dichloride and/or vinyl chloride, and to producing an organic polysulfide polymer mixture having low odor. This modified polysulfide polymer mixture is derived from the heavy ends waste using an enrichment technique to reduce the ethylene dichloride content.
2. Information Disclosure Statement
The polymerization of inorganic polysulfides with polyfunctional organic compounds is well known in the art. U.S. Pat. No. 1,890,191, teaches that suitable polyfunctional compounds which are alkyl dihalides polymerize with metal polysulfide to form a linear polysulfide polymer. The preferred polyfunctional monomers are dichloroethane, ethylene dichloride, dichloroethyl ether, dichloroethyl formal and trichloropropane and/or their mixtures and the preferred metallic polysulfide is sodium polysulfide. The commercial polysulfide polymers currently available are synthesized from dichloroethyl formal with a small amount of trichloropropane. Polysulfide polymers derived from other materials usually emit an offensive odor thereby limiting their use.
Although many patents teach the production of polysulfide polymer from pure starting chemicals and/or their mixtures, very few process use heavy ends waste as a raw material. U.S. Pat. Nos. 4,025,495 and 4,102,874 in 1977 and 1978 respectively disclosed converting a heavy residue derived from vinyl chloride manufacture into an organic polysulfide polymer. The obnoxious odor produced from such a polysulfide polymer, however, limits its application. Consequently, this product and the processes of making it have never been commercially utilized.
In 1949, U.S. Pat. No. 2,466,963 disclosed an improved process to prepare a liquid polysulfide polymer. The high molecular weight polysulfide polymer formed by reacting an alkaline polysulfide with a mixture of bis-2-chloroethyl formal and 1,2,3,-trichloropropane is reductively cleaved or split with sodium hydrosulfide and sodium sulfate to form a lower molecular weight material with essentially all disulfide linkages. The liquid polysulfide polymer obtained from this process, however, contains low molecular weight mercaptan compounds with undesirable odors. These odors generally limit the application of liquid polysulfide polymer sealant to well ventilated areas.
A number of disclosures relate to methods of reducing the unpleasant odor associated with the polysulfide polymer. For example, in 1963, U.S. Pat. No. 3,101,326 claimed that styrene oxide can be utilized as an effective masking agent to reduce or eliminate the offensive mercaptan odor of a polysulfide polymer. The reaction of polysulfide with styrene oxide, however, may affect the physical and/or chemical properties of polysulfide polymer and consequently limit its application to certain end cured products.
Therefore, a need exits to produce a low odor polysulfide polymer from the heavy end waste of chlorinated hydrocarbon 10 production. The present invention fulfills this need.